Heater Blower HELP!

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Ian_Fearn
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Heater Blower HELP!

Post by Ian_Fearn »

My heater blower is playing up.

On 'full' setting sometimes it works full blast but most of the time its hardly even blowing. Everynow and again you can hear it changing but generally goes back to being lame.

I've got a new blower unit but before I put it on is there some kind of resistor in this system??

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citronut
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Post by citronut »

yes the heater fan resistor pack is in the rear face of the heater fan box, in the scuttle under the wind screen,

GSF used to sell them cant remember how much,

but here are the OE part No.'s



6445 84
CONTROL MODULE
- UNTIL RPO No. 03709



6445 90
- SINCE RPO No. 03710


it wont let me check price at the mow

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mat_fenwick
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Post by mat_fenwick »

It's not actually a resistor pack, but contains a transistor to vary the voltage across the fan motor. To check if the existing motor is OK, you can unplug the two (thick) wire connector that comes out of the motor casing. If it spins then the motor is obviously OK.
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ken newbold
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Post by ken newbold »

If it's working intermittently I'd suspect it's either the motor itself or the speed control on the dashboard.

If you unplugged the transistor and shorted out a couple of the wires, you should have full blow. If it's still intermittent it's you motor and probably just the brushes.
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Post by mat_fenwick »

mat_fenwick wrote:It's not actually a resistor pack, but contains a transistor to vary the voltage across the fan motor. To check if the existing motor is OK, you can unplug the two (thick) wire connector that comes out of the motor casing and connect it to a 12V supply. If it spins then the motor is obviously OK.
Sorry about that, must be the Christmas spirit(s!) affecting my typing/thinking ability...
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Post by kiwi »

Just a quick slight off topic with this.

Would this also cause the fan to stay on? The TRS has its fan on permanatly low speed cant switch it off. Not much of a worry either been like it since I got it.
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Post by ken newbold »

I wouldn't have thought so :? normally when the transistor fails it either goes into full blow or no blow at all :?
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Post by docchevron »

kiwi wrote:Just a quick slight off topic with this.

Would this also cause the fan to stay on? The TRS has its fan on permanatly low speed cant switch it off. Not much of a worry either been like it since I got it.
Ooh, I read something about this recently, only I can't remember where now!
But someone else (could even have been on AF) had the same problem and was told by the garage that Oz spec cars always had the blowers running, there was no way to shut them off.
Which seems odd to me, and I've never heard of that before.

I think in that instance I'd be looking at the PCB in the fascia?
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Post by kiwi »

docchevron wrote: was told by the garage that Oz spec cars always had the blowers running, there was no way to shut them off.
Which seems odd to me, and I've never heard of that before.

I think in that instance I'd be looking at the PCB in the fascia?
Nothing would surprise me but the TZS does not have that issue. Good job to because when the Aircon is blowing even with the fan off it is still effectively cold.... cough need it today temperature reached 26c 8)
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Post by Dollywobbler »

Hold on - I though BX heater fans always ran, or is it just the case that all three BXs I've owned have a faulty blower control? Turn it all the way, and the system shuts off completely but even slightly turned, the fan blows slightly.
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Post by ken newbold »

Dollywobbler wrote:Hold on - I though BX heater fans always ran, or is it just the case that all three BXs I've owned have a faulty blower control? Turn it all the way, and the system shuts off completely but even slightly turned, the fan blows slightly.
This is true, but the fan does shut off :)
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Post by kiwi »

ken newbold wrote:
Dollywobbler wrote:Hold on - I though BX heater fans always ran, or is it just the case that all three BXs I've owned have a faulty blower control? Turn it all the way, and the system shuts off completely but even slightly turned, the fan blows slightly.
This is true, but the fan does shut off :)
I agree with that. In effect all you have done by turning the fan off is stopped the forced flow. The BX airvents are open still and an air flow is coming in through as a natural airflow.

The TRS I have as sooon as you put the key in the ignition you can hear the fan on a low speed hence my question which I think Doc may well have answered.

Thankfully the famous blocked tap does not affect this car so I dont have a slightly more warmed airflow into the car duuring the summer months :lol:
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Re: Heater Blower HELP!

Post by Jaba »

Ian_Fearn wrote:My heater blower is playing up.
Sounds like the best thing to do is to put your other motor in.
Especially if your blower motor does not run at a steady speed at the intermediate settings.

That power regulator (resistor) does play up but usually it just packs up altogether. This can be due to a poor earth connection via a sort of retaining strap and some electrically conducting grease that is used that just dries up. Worth a look and clean up if the new motor still plays up.

The tracking of the speed control dial also plays up with age. Again this shows up mostly at the higher speed settings where it has to pass a bit more current - but I would try the motor first.
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Post by kiwi »

One thing I noticed no one has mentioned is the spindle sticking.

Ian does your fan screech to a halt or screech at all? If so look at the spindle but your probably going to find any fix unless a complete overhaul is temporary so its really an easy job to just swamp the fans over, than fiddle around.
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Post by maxgreenwood »

my blower wasn't working but tested ok bridging the car battery into the socket on the motor, this is a simple test. i tried resoldering pcb board with no success. It was heavily corroded. got another one and has worked great since, the simple soldering modification posted on this forum for full fan speed is handy in winter as well.
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